package cn.tanghom.support.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import cn.tanghom.app.system.model.User;
import cn.tanghom.app.system.service.UserService;
import cn.tanghom.conf.CommonKey;
import cn.tanghom.support.db.DynamicDataSourceHolder;
import cn.tanghom.support.web.ContextHolder;

public class LoginIntercepter extends HandlerInterceptorAdapter{
	@Autowired
	private UserService userService;
	/**  
     * 在业务处理器处理请求之前被调用  
     * 如果返回false  
     *     从当前的拦截器往回执行所有拦截器的afterCompletion(),再退出拦截器链 
     * 如果返回true  
     *    执行下一个拦截器,直到所有的拦截器都执行完毕  
     *    再执行被拦截的Controller  
     *    然后进入拦截器链,  
     *    从最后一个拦截器往回执行所有的postHandle()  
     *    接着再从最后一个拦截器往回执行所有的afterCompletion()  
     */    
    @Override    
    public boolean preHandle(HttpServletRequest request,    
            HttpServletResponse response, Object handler) throws Exception {     	
        String username =  (String)request.getSession().getAttribute("username");          
        if(username == null){  
            request.getRequestDispatcher("login").forward(request, response);  
            return false;  
        }else{  
        	User user = (User) request.getSession().getAttribute(CommonKey.USER_SESSION);
        	if(user==null){
        		user = this.userService.findByLoginName(username);
        	}
        	if(user!=null){        	  
            	 ContextHolder.setSession(request.getSession());
            	 ContextHolder.setUser(user);
            }
            return true;     
        }
    }    
    
    /** 
     * 在业务处理器处理请求执行完成后,生成视图之前执行的动作    
     * 可在modelAndView中加入数据，比如当前时间 
     */  
    @Override    
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,    
            ModelAndView modelAndView) throws Exception {  
    	User user = ContextHolder.getUser();
    	if(user==null){
    		String username =  (String)request.getSession().getAttribute("username");
    		user = this.userService.findByLoginName(username);
    	}    	
    	request.setAttribute(CommonKey.CURRENT_USER, user);        
    }    
    
    /**  
     * 在DispatcherServlet完全处理完请求后被调用,可用于清理资源等   
     *   
     * 当有拦截器抛出异常时,会从当前拦截器往回执行所有的拦截器的afterCompletion()  
     */    
    @Override    
    public void afterCompletion(HttpServletRequest request,    
            HttpServletResponse response, Object handler, Exception ex)    
            throws Exception {    
    }    
  
}
